After testing with milsurp 3300fps and hand-loaded 2700fps 55gr ammo I have determined that the stock RECON gas system is over-gassed as you cannot turn down the gas venting adjustment enough to make the rifle fail to feed.

This indicates that the rifle is beating its-self to death.

This is why OpRods break (Aside from machining tolerances).

I have a solution in the works which will increase the adjust-ability of the gas regulation system so that it actually functions as intended and reduces wear/recoil.

If everything goes well, I will have replacement OpRod springs available as a result.

This is an awesome rifle; it just doesn't have 50+ years of service and refinement like the AR15 design does.

OK, Ive done the experimentation with the FAL OUTER recoil springs and while they can be made to make the rifle function for a while they are too weak for the application.

As they are shortened in order to allow the carrier to impinge upon the recoil plate, they yield less spring tension. (Down to around 10 lbs after clipping 11 coils which is far lower than the ~ 15 lbs of the original spring).

The diameter of the wire and the pitch/spacing of the FAL OUTER spring provides far less resistance than the original spring and thus, weaker. No Go.

I''m going to consult a spring manufacturer next and see what it will cost me to have custom springs made in several spring pressures so we can get these rifles shooting like they were intended.

The gas relief/adjustment system configuration at the gas-block has me concerned as it will be difficult to tune due to the gas flow but we obviously need stronger springs.

Later.

Let me know if there is any interest in this as it will affect the quality of my effort going forward.

I have been working the spring calcs and have a spring manufacturer involved and we both conclude that the original OpRod spring design was a trade-off between just getting the rifle to function and its reliability. (The gas adjustment system is not effective as designed as it offers little to nothing in the operation of the rifle as far as I am able to determine).

The springs as designed are over-stressed for the application, so they are going to fail.

They need to be replaced as needed and are a maintenance part - I would suggest that they are replaced after every 4 ~ 5 K rounds fired if they last that long.
Frequent and prolonged mag-dumps are going to reduce the life expectancy of the spring due to heat.

There is only one solution for this which requires a complete OpRod/Spring assembly redesign which I have conceptualized but the manufacturing of that product will be cost prohibitive.

I will, as a hobby attempt to complete the redesign and manufacture the parts for my own rifle but cannot see this limited market bearing the expense to make it worthwhile as something which can be brought to those owning these rifles in any quantity.

Too much manufacturing time/tooling/material waste and cost to make a perfect OpRod.

So, since the rifle runs (and not optimally) I will focus upon making original replacement copies of OpRods and Operating Springs in the stock/original configuration for general purchase knowing that these parts will need replacing at some regular interval.

Best to have extra parts, IMO.

The next thing that I see which is going to fail is the Bolt-camming boss and that is not going to be easy to make nor come-by . . .

I still need feedback concerning the gas system adjust-ability and its effects upon the rifles' function - post the info as you are able - Can you make it fail to cycle on a setting of "5" on the gas regulator?

I have spent too many hours running calculations in order to match the original RECON OpRod spring characteristics using other materials/spring designs than Piano Wire and it cannot be done.
It just isn't going to work.
This (Piano Wire) is what the rifle was originally designed around and you cannot make it better (functionally) by substituting a different material.

Call my effort "Reverse Engineering" but it is what it is. (Alex is said to be an assh-le - But If I were to have tried and successfully made a new combat weapon for the general public during the Assault Weapons Ban Era and someone got on my back about ANYTHING; I WOULD be an assh-le TOO!)

The OpRod spring is a wear/maintenance part and you just have to deal with that. (Keep it clean and dry and it will last).

Looks like I can get them made but it is going to cost me dearly to get a run done - If I buy 50 at a time I get a pretty good deal.